Simultaneous total occlusion due to spasm of 2 main coronary arteries: A case report

Rationale: Coronary artery spasm (CAS) defined by severe reversible focal or diffuse vasoconstriction, plays an essential role in the pathophysiology of acute coronary syndrome but is not very common in the clinic. Due to its transience, it is difficult to diagnose CAS directly, many patients are diagnosed by clinical experience. Here, we report the diagnosis and treatment of a rare case of simultaneous total occlusion due to spasm of the two main coronary arteries by coronary angiography (CAG). Patient concerns: A 47-year-old man with no medical history was admitted to our emergency room complaining of sudden-onset chest pain lasting 3 hours. Emergency CAG showed total occlusion of the proximal left anterior descending artery and right coronary artery. Diagnoses: Acute myocardial infarction caused by CAS was diagnosed, according to CAG findings and test results. Interventions: Intracoronary injection of nitroglycerin and anti-spasm medication. Outcomes: The patient was discharged on the 8th day with complete resolution of symptoms and normalization of the electrocardiography findings. No ischemic events occurred during a follow-up for 27 months. Lessons: This case highlights the significance of identifying CAS in patients with acute myocardial infarction and avoiding blind interventional stent therapy, which requires closer attention from clinicians.


Introduction
Coronary artery spasm (CAS), which is a sudden and reversible vasoconstriction that decreases the lumen of normal or atherosclerotic coronary arteries influencing myocardial blood flow, is characterized by ischemia with no obstructive coronary artery. [1] Despite its transient nature, patients with CAS may present with angina or life-threatening heart events, such as acute myocardial infarction (AMI), lethal arrhythmias, and even sudden death, especially in the case of multivessel involvement. [2] To the best of our knowledge, some cases of CAS have been reported, however simultaneous total occlusion caused by spasm of the 2 main coronary arteries has not been previously reported.

Case presentation
A 47-year-old man with no significant medical history and no prior complaints of chest pain was admitted to the emergency department with sudden-onset chest pain characterized by squeezing in the left parasternal area that persisted for 3 hours without precipitating factors. He had a smoking history of 20 years, and no family history of coronary artery disease.
On admission, his heart rate was 73 beats/min, blood pressure was 101/78 mm Hg, and physical examination was negative. Electrocardiography (ECG) revealed sinus rhythm with ST-segment elevation in the widespread anterior, inferior, and right precordial leads (V1-V6, II, III, avF, and V3R-V5R) Medicine and reciprocal ST-segment depression in the lateral leads (I and aVL) (Fig.1). Hypersensitive cardiac troponin I test was negative.
Emergency coronary angiography (CAG) was performed (Fig.2), and demonstrated simultaneous complete occlusion of the proximal left anterior descending artery (LAD) and proximal right coronary artery (RCA). We decided to perform percutaneous coronary intervention for him. Surprisingly, LAD became completely normal after intracoronary administration of nitroglycerin 200 µg in it, and the same phenomenon occurred in the RCA. Organic coronary stenosis was not observed. The patient's symptoms were generally alleviated. Electrocardiographic monitoring revealed recovery of ST-segment elevation. During angiography, low blood pressure and slow heart rate occurred, which returned to normal after intravenous injection of vasoactive drugs (epinephrine, atropine, dopamine, and norepinephrine).
Then, the patient was monitored in the Cardiac Care Unit. The ECG in the Cardiac Care Unit showed an ST-segment almost back to the baseline (Fig.3). Laboratory result showed hypersensitive cardiac troponin I levels of 50 ng/mL at the peak (normal range 0-0.06 ng/mL), low-density-lipoprotein cholesterol (LDL-C) level was 3.36 mmol/L (normal range 1.0-3.1 mmol/L). While other laboratory tests results were within normal ranges. Echocardiography presented a new inferior left ventricular wall and post-ventricular septum hypokinesis, with an estimated left ventricular ejection fraction of 60%.
Based on the medical history, CAG findings, and test results, the diagnosis of AMI was ultimately made with simultaneous total occlusion due to persistent spasm of the 2 main coronary arteries. Lifestyle changes were recommended, including cessation of smoking and long-term medicines were administrated including diltiazem, isosorbide mononitrate, aspirin, clopidogrel, and atorvastatin. During hospitalization, the patient did not have any discomfort and no arrhythmias occurred. On the 8th day of admission, the patient was discharged with complete resolution of symptoms and normalization of the ECG findings. During regular outpatient follow-up for 27 months, no major adverse cardiac events occurred, and no angina was reported by him.

Discussion
CAS is uncommon in patients with ischemic heart disease irrespective of racial, genetic, and geographic variations. [1] The concept of CAS was first proposed by Prinzmetal et al by describing non-exertional angina occurring during regular daily activities or at rest, [3] which was later confirmed and demonstrated in several experimental studies. There have been reported many cases of CAS due to different situations, for example, Piel et al [4] and Bai L et al [5] reported extreme ST-segment elevations due to CAS, Xin Xie et al [6] reported severe CAS during left atrial appendage closure plus catheter ablation for atrial fibrillation, but simultaneous total occlusion of the 2 main coronary arteries caused by CAS has not been reported, therefore, we reported this case in which a patient suffered from persistent LAD and RCA spasm, even occlusion, who eventually presented with myocardial infarction.
The manifestations of CAS according to the coronary segments and frequencies of angina onsets vary vastly from asymptomatic to angina, AMI, ventricular arrhythmias, and sudden cardiac death. [7] Unlike vasovagal symptoms, CAS occurs regularly at rest and early in the morning, between midnight and 5 am. [8] The main risk factors for CAS are smoking, age, LDL-C level, hypertension, diabetes mellitus, and high-sensitivity C-reactive protein level. [9] CAS is more common in males than females aged between 40 and 70 years. [1,10] Smoking was considered to be involved in the onset of CAS, which would trigger vascular injury, a decline in the partial pressure of oxygen in the myocardium and coronary arterial flow. [11] There was a positive correlation between coronary arterial contraction and LDL-C and total cholesterol levels during CAS. [12] High concentration of LDL-C can affect the prognosis of patients with CAS. The coexistence of several risk factors can strengthen the ability to induce CAS, which may lead to a vicious circle. In the present case, the patient was a 47-year The underlying pathophysiology of CAS is not clearly understood, which could have multifactorial implications on the autonomic nervous system, inflammation, endothelial dysfunction, atherosclerosis, thrombosis and hyperreactivity, etc. [1] The potential mechanism of CAS in this case may involve the following aspects: the first is the patient's risk  factors of smoking and high LDL-C levels, which would contribute to chronic inflammation and atherosclerosis, resulting in hyperreactivity and increasing the risk of CAS. In addition, the autonomic nervous system plays an important role; the parasympathetic nervous system is supported by the frequent occurrence of CAS at midnight or rest correlating with the highest vagal activity. [13] Our patient had angina at rest, confirming this hypothesis.
The most reliable method for diagnosing coronary vasospasm is the provocation test adjunctive to CAG, [14] which is rarely performed owing to serious side effects, although it has been confirmed to be safe and has relevant prognostic implications.
Coronary imaging can be used to detect CAS specific findings. Intravascular ultrasound can identify small lesion plaque volume and burden, diffuse coronary intimal thickening, and different plaque components. Nevertheless, optical coherence tomography can delineate detailed structural changes in the coronary arteries of patients with CAS. In our case, we confirmed CAS in the LAD and RCA by CAG. However, we were unable to perform intravascular ultrasound or optical coherence tomography to identify the possible mechanism due to the cost, state of the patient, and invasive method.
The treatment of CAS mainly involves lifestyle changes (such as smoking cessation), antispasmodic medications and other cardiovascular protective therapy. [2] Nitrates remain a critical treatment to relieve acute attacks of CAS, [15] which can relax the smooth muscles and subsequently relieve spasmodic pain. However, owing to drug-related issues, long-term use of nitrates is not recommended unless it is effective. Long-acting calcium channel blockers (CCBs) are beneficial to myocardial oxygen supply in patients with CAS. A near-complete reduction in CAS recurrence is observed with nondihydropyridine CCBs (e.g., diltiazem) rather than with dihydropyridine CCBs. [16] Studies have documented a positive role for statins in suppressing CAS episodes and decreasing the risk of recurrence by improving endothelia function. [17,18] Antiplatelet therapy plays a controversial role. Stenting is only recommended in patients with CAS and significant stenosis of the coronary artery. [19] Implantable cardiac defibrillator therapy is limited to life-threatening situations defined by cardiac arrest survivors and episodes of ventricular arrhythmia. [19,20] CAS can lead to lethal arrhythmia and silent angina. However, implantable cardiac defibrillator indications remain unclear and are recommended for secondary prevention. For this patient, with the above medical treatment, no major adverse cardiovascular events occurred.

Conclusion
CAS is a complex multifactorial disease that can lead to serious complications, which often present as local or whole arteries, and occurs in 2 or 3 arteries at different times or simultaneously in the same patient. However, simultaneous total occlusion caused by spasms of the 2 main coronary arteries, which is a severe or lethal condition, is rare. Physicians should consider this condition to better recognize it early and start appropriate treatment, which would prevent the aggravation of spasm attacks and improve long-term outcomes.